Vehicle seat

ABSTRACT

A vehicle seat comprises: a base frame (side frame  4,  pipe frame  5 ) which constitutes at least left and right lower portions of a seat back frame; a force-receiving member (bracket  7 ) disposed adjacent to a left or right outer side of the base frame, and configured to receive a load from outside in a lateral direction; and a load transmission part configured to transmit the load from the force-receiving member to a side laterally opposite to that on which the force-receiving member is provided, wherein the force-receiving member has a shape with a closed cross section, and a portion of at least one of an upper wall ( 72 ) and a lower wall ( 74 ) separate from front and rear ends thereof provides an uneven shape (stepped profile  72   a,    74   a ).

TECHNICAL FIELD

The present invention relates to a vehicle seat in which a sidecollision load on a vehicle can be transmitted laterally from outsidetoward inside.

BACKGROUND ART

A vehicle seat comprising a pipe frame (inner frame) shaped like arectangular loop, a plate-like side frame disposed adjacent to a left orright outer side of the pipe frame, and a bracket (force-receivingmember) fixed to a left or right outer side of the side frame hashitherto been known in the art (see JP 2000-103275 A). In thistechnique, the bracket is shaped like a box having front, rear, upperand lower sides all of which are flat, and when a side collision loadimposed on the vehicle is received by the bracket from outside in alateral direction, this side collision load is transmitted through therespective flat surfaces inward in the lateral direction.

However, with the conventional technique, since the sides of the bracketfor transmitting a side collision load are flat, these flat sides ofbracket, if their wall thickness is thin, would be buckled upon receiptof a side collision load, with the result that the loaddisadvantageously could not properly be transmitted inward in thelateral direction.

Against this backdrop, the inventors named in the present applicationhave created the present invention in an effort to provide a vehicleseat in which a load can be properly transmitted laterally from outsidetoward inside even if the wall thickness of the bracket (force-receivingmember) is thin.

SUMMARY OF INVENTION

Specifically, a vehicle seat according to one aspect of the presentinvention comprises: a base frame which constitutes at least left andright lower portions of a seat back frame; a force-receiving memberdisposed adjacent to a left or right outer side of the base frame, andconfigured to receive a load from outside in a lateral direction; and aload transmission part configured to transmit the load from theforce-receiving member to a side laterally opposite to that on which theforce-receiving member is provided. The force-receiving member includesan upper wall and a lower wall and has a shape with a closed crosssection, and a portion of at least one of the upper wall and the lowerwall separate from front and rear ends thereof provides an uneven shape.

With this configuration, since at least one of the upper and lower wallsof the force-receiving member has a portion separate from the front andrear ends thereof which portion has an uneven shape, the rigidity ofthat portion of the wall(s) having the uneven shape is thus increased,so that the wall(s) can be prevented from being buckled even if the wallthickness of the force-receiving member is thin; therefore, the loadreceived from laterally outside toward inside can be transmittedeffectively. In addition, since the uneven shape is not provided on thefront and rear ends of the upper wall and the lower wall, the front endand rear end corners of the upper wall and the lower wall can be formedcontinuously in the lateral direction, so that these continuous cornerscan effectively transmit the load from outside to inside in the lateraldirection.

In the above-described configuration, the uneven shape may be of astepped profile formed by overlapping two plate-like portions.

With this feature, since the overlapped portion of the two plate-likeportions is rendered thicker, the rigidity can be enhanced.

Moreover, the stepped profile may be continuously formed from the atleast one of the upper wall and the lower wall to an outer wall locatedat a laterally outer side of the force-receiving member.

With this feature, since the thicker portion is continuously formed fromthe outer wall to the upper wall or the lower wall, a load received atthe outer wall can be effectively transmitted to the upper wall or thelower wall.

Furthermore, the force-receiving member may be segmented in front andrear halves of box-like members which are fitted together, andconfigured such that the stepped profile is formed as a result offitting the box-like members together, continuously across the upperwall, the outer wall and the lower wall.

With this feature, since the thicker portion of the outer wall extendscontinuously to the upper wall and the lower wall, a load received atthe outer wall can be transmitted effectively through the upper wall andthe lower wall in a laterally inward direction.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a vehicle seat according to oneembodiment of the present invention;

FIG. 2 is an enlarged perspective view of a bracket and its surroundingstructure as viewed from the front;

FIG. 3 shows (a) section I-I, (b) section II-II, and (c) section of FIG.2;

FIG. 4 is an enlarged perspective view of the bracket and itssurrounding structure as viewed from the rear; and

FIG. 5 includes (a) a perspective view showing an embodiment having astepped profile formed only on an upper wall, and (b) a perspective viewshowing an embodiment having a stepped profile formed continuously onlyon the upper wall and an outer wall.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereafter, a description will be given of one embodiment of the presentinvention with reference to the drawings.

A vehicle seat according to the present invention is made up of a seatframe 1 as shown in FIG. 1 the outside of which is covered with a seatcushion made of urethane foam or the like. The seat frame 1 includes aseat back frame 2 and a seat bottom frame 3. It is to be understood thatin describing the present invention, the front/rear, left/right andupper/lower are defined as viewed from an occupant sitting on the seat.

The seat back frame 2 is configured to include a pair of side frames 4and a pipe frame 5 as one example of a base frame, a lower frame 6 asone example of a load transmission part, and a bracket 7 as one exampleof a force-receiving member.

The side frames 4 are plate-like members which constitute left and rightlower portions of the seat back frame 2, and each configured to protrudefrontward (in at least one of the front and rear directions) beyond thepipe frame 5, as shown in FIG. 2. This configuration provides afrontwardly overhanging shape formed at each side of the seat back, andallows an air bag or other parts to be securely fixed to the frontwardlyand rearwardly extending plate-like side frames 4.

To be more specific, as shown in FIG. 3( a), each side frame 4 has athrough hole 41 pierced through the left and right sides at anappropriate position thereof, and a front portion 42 thereof is bentinwardly to the left or to the right and further bent to the rear toform a U-shaped cross section. This configuration serves to improve therigidity of the front portion 42 of the side frame 4.

A rear portion 43 of each side frame 4 is bent inwardly to the left orto the right to form an L-shaped cross section, and is joined to thepipe frame 5 by welding. In FIG. 3( a), welds or spots welded by awelding torch T are illustrated with exaggerated black dots.

As shown in FIG. 1, the pipe frame 5 is a reinforcing frame forreinforcing the side frame 4, having a cylindrical shape (with a closedsection), which is bent into a shape of a substantially rectangularloop. Left and right lower portions of the pipe frame 5 are disposedadjacent, and joined, to laterally inner sides of the side frames 4,respectively. With this configuration, a lower portion 51 (includingportions extending obliquely downward from the portions adjacent to theside frames 4) of the pipe frame 5 is configured to serve, incombination with the lower frame 6, as a load transmission part, totransmit a load to the left or to the right.

Two wires W bent to ascend and descend several times are provided inpositions spaced out vertically, and joined to left and right sideportions 52, 53 of the pipe frame 5, and a pressure-receiving member Cshaped like a plate and made of plastic are fixed to these wires W. Withthis configuration, when the vehicle receives a rear-end collision load,the occupant subsides rearward together with the receiving member Cinside the pipe frame 5, and thus the impact of the rear-end collisionload against the occupant can be softened.

The lower frame 6 is a plate-like member extending laterally, which isjoined to the lower portions of the side frames 4 and to the lowerportion 51 of the pipe frame 5. With this configuration, a load imposedon the bracket 7 from outside in the left or right direction istransmitted through the lower frame 6 and the lower portion 51 of thepipe frame 5 to the side laterally opposite to that on which the bracket7 is provided.

The bracket 7 is a part provided discretely from the pipe frame 5 andthe side frames 4, and disposed adjacent, and joined, to the left side(laterally outer side) of the left side frame 4 (one of the side frames4). To be more specific, the bracket 7 is disposed near a side panelsuch as a side pillar or a door of the vehicle, so that a side collisionload imposed on the vehicle is received thereby.

The bracket 7 is, as shown in FIG. 2, directly fixed by welding to thepipe frame 5 through two through holes 41 (opening) formed in the sideframe 4. With this configuration, irrespective of the angle andmagnitude of the side collision load received, the load can betransmitted properly from the bracket 7 to the pipe frame 5 withoutgetting affected by deformation of the side frame 4. In FIG. 2 and FIG.4, the welded spots are illustrated with shades of dots.

To be more specific, the bracket 7 is segmented in front and rear halvesof a front-side box-like member 8 and a rear-side box-like member 9which are fitted together, and configured such that the box-like members8, 9, once combined together, form a closed section as taken along aplane perpendicular to the lateral direction.

The front-side box-like member 8 includes a plate-like front wall 81elongated in the upward-and-downward direction longer than extending inthe lateral direction, an upper wall 82 extending from an upper end ofthe front wall 81 rearward, an outer wall 83 extending from a laterallyouter end of the front wall 81 rearward, and a lower wall 84 extendingfrom a lower end of the front wall 81 rearward, all of which areprovided integrally. In other words, the front-side box-like member 8 isconfigured to have a shape of a box which opens to the rear and to alaterally inner side.

In the front wall 81, two recessed portions 81 a (providing an unevenshape) disposed in a portion separate from upper and lower ends of thefront wall 81 and configured to be recessed inwardly in the front-reardirection are arranged in positions spaced out vertically at apredetermined distance. With this configuration, the rigidity of thefront wall 81 is enhanced, and thus a side collision load can betransmitted effectively to the pipe frame 5 by the high-rigidity frontwall 81. Moreover, since the recessed portions 81 a are formed in theportion of the front wall 81 separate from the upper and lower endsthereof, the upper and lower end corners of the front wall 81 can beformed continuously in the left-right direction, so that the continuouscorners can effectively transmit the load from outside to inside in thelateral direction.

Each recessed portion 81 a is formed at a laterally inner end portion 81b of the front wall 81, and thus opens to the front and to the laterallyinner side. With this configuration, an edge 81 c of the end portion 81b is bent to the front and to the rear, and thus the rigidity of theedge 81 c located at an output side of the side collision load can beincreased, so that the side collision load can effectively betransmitted to the pipe frame 5 or the like.

Each recessed portion 81 a has a bottom wall 81 d, at which an extensionportion 81 e (part of the force-receiving member provided at a laterallyinner side thereof) extending laterally inward beyond the edge 81 c ofthe front wall 81 is formed. This extension portion 81 e is disposedinside the through hole 41 of the side frame 4 described above, andextends to the pipe frame 5, so that the extension portion 81 e abuttingon the pipe frame 5 is welded to the pipe frame 5.

Since only the extension portion 81 e is passed through the through hole41, the through hole 41 may be sized to conform to the extension portion81 e, and thus the through hole 41 may be made smaller so that therigidity of the side frame 4 can be enhanced. To be more specific, inthe present embodiment, the through hole 41 is shaped like an elongatehole having dimensions smaller than the width of the pipe frame 5 in afront-rear direction, and smaller than the whole length of the edge 81 cof the front wall 81 and greater than the extension portion 81 e in avertical direction.

The size of the through hole 41 may be designed to have, at the largest,an area comparable or smaller than a cross-sectional area of a laterallyinner end portion (adjacent an end located at a side from which the sidecollision load is outputted) of the bracket 7. The through hole 41formed to have a size described above makes it possible to impart ahigher rigidity of the side frame 4, for example, in comparison with athrough hole formed in the side frame to have such a size as to allowthe laterally inner end portion of the bracket 7 to be passed through inits entirety.

Although the extension portion 81 e is provided in the presentembodiment, the present invention is not limited to this configuration;i.e., a configuration without the extension portion 81 e may also bepossible. In this configuration, some gap may be left between the pipeframe 5 and the edge 81 c of the front wall 81, but this gap stillpermits welding by which the pipe frame 5 and the bracket can be joineddirectly.

The extension portion 81 e is, as shown in FIG. 3( a), fixed to acentral portion 5 a located at a center in the front-rear direction ofthe pipe frame 5. With this configuration, the load from the bracket 7is transmitted intensively to the central portion 5 a of the pipe frame5, and thus the load can be transmitted more effectively.

A center 5 b in the front-rear direction of the pipe frame 5 is locatedwithin a width in the front-rear direction of the bracket 7. With thisconfiguration, upon side collision, the load can be transmitted moreeffectively because the bracket 7 can be prevented from slipping out tothe front or to the rear on a cylindrical outer surface of the pipeframe 5.

As shown in FIG. 2, an upper portion and a lower portion of the edge 81c of the front wall 81 are fixed to the side frame 4 by welding. Inother words, the front wall 81 is fixed directly to both of the sideframe 4 and the pipe frame 5. With this configuration, the load receivedby the bracket 7 is transmitted not only through the pipe frame 5 butalso through the side frame 4 to the load transmission part (the lowerframe 6 and the lower portion 51 of the pipe frame 5), and thus moreeffective transmission of the load can be ensured. It is appreciatedthat the load transmitted to the load transmission part can betransmitted to the vehicle body side through a console box or the likeprovided at a side opposite to that on which the bracket 7 is provided.

As shown in FIG. 4, the rear-side box-like member 9 includes aplate-like rear wall 91 elongated in the upward-and-downward directionlonger than extending in the lateral direction, an upper wall 92extending from an upper end of the rear wall 91 frontward, an outer wall93 extending from a laterally outer end of the rear wall 91 frontward,and a lower wall 94 extending from a lower end of the rear wall 91frontward, all of which are provided integrally. In short, the rear-sidebox-like member 9 is configured to have a shape of a box which opens tothe front and to the laterally inner side.

In the rear wall 91, two recessed portions 91 a (providing an unevenshape) disposed in a portion separate from upper and lower ends of therear wall 91 and configured to be recessed inwardly in the front-reardirection are arranged in positions spaced out vertically at apredetermined distance. With this configuration, the rigidity of therear wall 91 is enhanced, and thus a side collision load can betransmitted effectively to the laterally inner side by the high-rigidityrear wall 91. Moreover, since the recessed portions 91 a are formed inthe portion of the rear wall 91 separate from the upper and lower endsthereof, the upper and lower end corners of the rear wall 91 can beformed continuously in the left-right direction, so that the continuouscorners can effectively transmit the load from outside to inside in thelateral direction.

Each recessed 91 a is disposed opposite to a corresponding recessedportion 81 a of the front-side box-like member 8 in the front-reardirection, whereas each bottom wall 91 d and a bottom wall 81 d of acorresponding recessed portion 81 a are disposed to adjoin to eachother, as shown in FIG. 3( a). With this configuration, the two bottomwalls 81 d, 91 d adjoining to each other constitute a thick portionlocated substantially at the center in the front-rear direction, andthus effective transmission of the side collision load can be achieved.

The two bottom walls 81 d, 91 d adjoining to each other are joinedtogether by welding. With this configuration, the rigidity of thebracket 7 can be enhanced, and thus effective transmission of the sidecollision load can be achieved.

The two bottom walls 81 d, 91 d adjoining to each other are locatedwithin a width in the front-rear direction of the pipe frame 5. Withthis feature, the side collision load can be effectively transmitted tothe pipe frame 5 through the thick portion made up of the joined bottomwalls 81 d, 91 d.

Furthermore, the center 5 b in the front-rear direction of the pipeframe 5 is located within a width in the front-rear direction of thethick portion made up of the joined bottom walls 81 d, 91 d. With thisconfiguration, the load can be transmitted intensively to the center 5 bor therearound of the pipe frame 5 through the thick portion made up ofthe joined bottom walls 81 d, 91 d.

As shown in FIG. 4, a laterally inner end 91 b of the rear wall 91 isfixed to the side frame 4 by welding. To be more specific, as shown inFIG. 3( a), the laterally inner end 91 b of the rear wall 91 is joinedto a closed section shaped portion made up of a rear portion 43, bentinto an L-shape, of the side frame 4 and a left-side rear portion of thepipe frame 5. With this configuration, the side collision loadtransmitted from the rear wall 91 to a laterally inner side is receivedproperly by the closed section shaped portion, and thus can betransmitted effectively to the pipe frame 5.

Furthermore, as shown in FIGS. 2, 3, the upper wall 92, outer wall 93and lower wall 94 of the rear-side box-like member 9 is disposed overthe upper wall 82, outer wall 83 and lower wall 84 of the front-sidebox-like member 8, and fixed to the walls 82-84, respectively bywelding.

With this configuration, as shown in FIG. 3( b), the upper wall 72 ofthe bracket 7 has a stepped profile 72 a (providing an uneven shape)formed, at a position separate from the front and rear ends thereof, byoverlapping the upper walls 82, 92 (two plate-like portions) of therespective box-like members 8, 9. With this configuration, a portion ofthe upper wall 72 substantially at the center thereof in the front-reardirection is formed as a thick portion by overlapping the upper walls82, 92, and thus the rigidity of the upper wall 72 can be enhanced, sothat a side collision load can be transmitted effectively.

Furthermore, since the stepped profile 72 a (providing an uneven shape)is formed in a position separate from the front and rear ends of theupper wall 72, the front and rear end corners of the upper wall 72 canbe formed continuously in the left-right direction, so that thecontinuous corners can effectively transmit the load from outside toinside in the lateral direction.

Similarly, as shown in FIGS. 3( a), (c), the outer wall 73 and lowerwall 74 of the bracket 7 also has stepped profiles 73 a, 74 a formed byoverlapping the outer walls 83, 93 and the lower walls 84, 94,respectively, of the box-like members 8, 9. With this configuration, therigidities of the outer wall 73 and the lower wall 74 as well can beenhanced, and the front and rear end corners of the lower wall 74 can beformed continuously in the left-right direction, so that the continuouscorners can effectively transmit the load from outside to inside in thelateral direction.

The stepped profiles 72 a, 73 a, 74 a are formed continuously across theupper wall 72, outer wall 73 and lower wall 74 of the bracket 7 as aresult of fitting the rear-side box-like member 9 on the front-sidebox-like member 8. With this configuration, the thick portion of theouter wall 73 is formed continuously to the thick portions of the upperwall 72 and the lower wall 74, and thus a side collision load receivedby the thick portion of the outer wall 73 can be transmitted effectivelyto the laterally inner side through the upper and lower continuous thickportions.

Advantageous effects of the vehicle seat according to the presentembodiment as described above are summarized hereinafter.

Since a portion of the upper wall 72 and the lower wall 74 of thebracket 7 separate from their front and rear ends is configured toprovide an uneven shape (stepped profiles 72 a, 74 a), the rigidity ofthe walls 72, 74 is enhanced; therefore, even if the wall thickness ofthe bracket 7 is thin, the walls 72, 74 are prevented from beingbuckled, so that a load can be transmitted effectively from outsidetoward inside in the lateral direction. Enhanced rigidity by this unevenshape allows the bracket 7 to be made thinner in wall thickness, and thevehicle seat to be made lighter in weight.

Since the uneven shape is not provided at the front and rear ends of theupper wall 72 and the lower wall 74, the front and rear end corners ofthe upper wall 72 and the lower wall 74 can be formed continuously inthe lateral direction; therefore, these continuous corners serve totransmit a load effectively from outside to inside in the lateraldirection.

Since the uneven shape is made of the stepped profile (stepped profile72 a) provided by overlapping two walls (e.g., upper walls 82, 92), theoverlapped portion of the two walls is rendered thicker, so that therigidity can be enhanced.

Since the stepped profiles 72 a, 73 a, 74 a are provided continuouslyacross the walls 72-74, i.e., the thicker portion of the outer wall 73extends continuously to the upper wall 72 and the lower wall 74, a loadreceived at the outer wall 73 can be transmitted effectively through theupper wall 72 and the lower wall 74 in a laterally inward direction.

Although the embodiment of the present invention has been describedabove, the present invention may be carried out into practice inappropriately modified configurations, as in the other embodimentsdescribed below.

In the above-described embodiment, the stepped profiles 72 a, 73 a, 74 aare provided continuously across the walls 72-74, but the presentinvention is not limited to this configuration; a stepped profile(uneven shape) provided merely in at least one of the upper wall and thelower wall may be advantageous. That is, for example, as shown in FIG.5( a), a stepped profile 711 a may be provided only at an upper wall 711of a bracket 710. In this configuration, as well, the rigidity of theupper wall 711 can be enhanced so that a load can be transmittedeffectively.

Moreover, the stepped profile provided continuously from at least one ofthe upper wall and the lower wall to the outer wall may suffice. Thatis, for example, as shown in FIG. 5( b), stepped profiles 721 a, 722 amay be provided continuously from an upper wall 721 to an outer wall 722of a bracket 720. In this configuration, as well, since the thickerportion of the outer wall 722 extends continuously to the upper wall721, a load can be transmitted effectively from the outer wall 722 tothe upper wall 721.

In the above-described embodiment, the stepped profile 72 a is adoptedas an uneven shape, but the present invention is not limited to thisconfiguration; for example, a recess or a protrusion may be adopted.

In the above-described embodiment, the base frame is configured tocomprise the side frame 4 and the pipe frame 5, but the presentinvention is not limited to this configuration; for example, it may beconfigured with a side frame only or with a pipe frame only.

In the above-described embodiment, a cylindrical pipe frame 5 is adoptedas an inner frame, but the present invention is not limited to thisconfiguration; for example, a pipe frame having a polygonal crosssection, a solid cylindrical member, or a solid prismatic member may beusable.

In the above-described embodiment, the force-receiving member isembodied in the bracket 7 composed of two box-like members 8, 9, but thepresent invention is not limited to this configuration; for example, abracket formed by bending or drawing a single plate-like member, forexample, as shown in FIG. 5( a), (b), may be usable.

In the above-described embodiment, the load transmission part isconfigured as an assembly of the lower frame 6 and the lower portion 51of the pipe frame 5, but the present invention is not limited to thisconfiguration. For example, in the above-described embodiment, the pipeframe 5 as the inner frame is formed integrally with the loadtransmission part (lower portion 51), but if the pipe frame is shapedlike a letter U which opens toward downward, a separate frame connectingthe lower end portions of the pipe frame may be provided as a loadtransmission part. Alternatively, if the lower portion 51 of the pipeframe 5 in the above-described embodiment is severed, with itsmidsection cut off, in two portions joined to the lower frame 6, thelower portions 51 extending halfway and the lower frame 6 may beconfigured as a load transmission part.

In the above-described embodiment, the bracket 7 and the pipe frame 5are fixed together by welding, but the present invention is not limitedto this configuration; for example, a bolt may be applied for fixingthese members together.

In the above-described embodiment, the through hole 41 is configured toserve as an opening, but the present invention is not limited to thisconfiguration; for example, the opening may be a hollow which opens tothe front or to the rear.

In the above-described embodiment, part of the bracket 7 (i.e.,extension portions 81 e) is passed through the opening (through holes41), but the present invention is not limited to this configuration;part of the inner frame may be passed through the opening and fixeddirectly to the bracket.

In the above-described embodiment, the inner frame (pipe frame 5) isconfigured to have a shape with a closed section in its entirety, butthe present invention is not limited to this configuration; it may beadvantageous only if at least a portion of the inner frame to which theforce-receiving member is fixed has a shape with a closed section.

1. A vehicle seat comprising: a base frame which constitutes at leastleft and right lower portions of a seat back frame; a force-receivingmember disposed adjacent to a left or right outer side of the baseframe, and configured to receive a load from outside in a lateraldirection; and a load transmission part configured to transmit the loadfrom the force-receiving member to a side laterally opposite to that onwhich the force-receiving member is provided, wherein theforce-receiving member includes an upper wall and a lower wall and has ashape with a closed cross section, and a portion of at least one of theupper wall and the lower wall separate from front and rear ends thereofprovides an uneven shape.
 2. The vehicle seat according to claim 1,wherein the uneven shape is of a stepped profile formed by overlappingtwo plate-like portions.
 3. The vehicle seat according to claim 2,wherein the stepped profile is continuously formed from the at least oneof the upper wall and the lower wall to an outer wall located at alaterally outer side of the force-receiving member.
 4. The vehicle seataccording to claim 3, wherein the force-receiving member is segmented infront and rear halves of box-like members which are fitted together, andconfigured such that the stepped profile is formed as a result offitting the box-like members together, continuously across the upperwall, the outer wall and the lower wall.